# Ds\Sequence::map

(PECL ds >= 1.0.0)

Ds\Sequence::map — Returns the result of applying a callback to each value

### Beschreibung

abstract public Ds\Sequence::map(callable `$callback`): Ds\Sequence

Returns the result of applying a `callback` function to each value in the sequence.

### Parameter-Liste

`callback`

  callback(mixed `$value`): mixed

  A callable to apply to each value in the sequence.

  The callable should return what the new value will be in the new sequence.

### Rückgabewerte

The result of applying a `callback` to each value in the sequence.

> Hinweis:

> The values of the current instance won't be affected.

### Beispiele

Beispiel #1 Ds\Sequence::map() example

`<?php
$sequence = new \Ds\Vector([1, 2, 3]);
print_r($sequence->map(function($value) { return $value * 2; }));
print_r($sequence);
?>`

Das oben gezeigte Beispiel erzeugt eine ähnliche Ausgabe wie:

    Ds\Vector Object
    (
        [0] => 2
        [1] => 4
        [2] => 6
    )
    Ds\Vector Object
    (
        [0] => 1
        [1] => 2
        [2] => 3
    )

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